GPSM1 impairs metabolic homeostasis by controlling a pro-inflammatory pathway in macrophages

G-protein-signaling modulator 1 (GPSM1) exhibits strong genetic association with Type 2 diabetes (T2D) and Body Mass Index in population studies. However, how GPSM1 carries out such control and in which types of cells are poorly understood. Here, we demonstrate that myeloid GPSM1 promotes metabolic inflammation to accelerate T2D and obesity development. Mice with myeloid-specific GPSM1 ablation are protected against high fat diet-induced insulin resistance, glucose dysregulation, and liver steatosis via repression of adipose tissue pro-inflammatory states. Mechanistically, GPSM1 deficiency mainly promotes TNFAIP3 transcription via the Gαi3/cAMP/PKA/CREB axis, thus inhibiting TLR4-induced NF-κB signaling in macrophages. In addition, we identify a small-molecule compound, AN-465/42243987, which suppresses the pro-inflammatory phenotype by inhibiting GPSM1 function, which could make it a candidate for metabolic therapy. Furthermore, GPSM1 expression is upregulated in visceral fat of individuals with obesity and is correlated with clinical metabolic traits. Overall, our findings identify macrophage GPSM1 as a link between metabolic inflammation and systemic homeostasis.

indicated WAT from GPSM1 f/f ; Lyz2-cre and GPSM1 f/f mice. n = 9 biologically independent mice per group. d, Representative H&E staining of scWAT, gonWAT and BAT sections.
Representative images of liver section (right). i, Liver weight (n = 9 biologically independent mice per group). j, Quantification of hepatic TG (n = 9 biologically independent mice per group). k, Serum levels of TCH, NEFA, ALT, and AST (n = 9 biologically independent mice per group). Independent experiments were repeated three times with similar results (d, h).
All data are shown as means ± SEM. P values are determined by unpaired two-tailed Student's t-test (b, c, e to g, i to k) or two-way ANOVA with Sidak's multiple-comparisons test (a, f, and g).

Supplementary Fig.5 Analysis of metabolic inflammation in HFD-fed mice.
a, Flow cytometry quantification of the Lin -Sca1 -cKit + myeloid precursors (MPCs) in the bone marrow of GPSM1 f/f and GPSM1 f/f ; Lyz2-cre mice both under NCD (12-week old) and HFD for 8 weeks (n = 5 biologically independent mice per condition). b, White blood cell counts both under the NCD (n = 5 biologically independent mice per group) and HFD settings (n = 6 biologically independent mice per group). NE, neutrophils; MO, monocytes; EO, eosinophils; BA, basophils; LY, lymphocytes. c, The numbers of Ly-6C low and Ly-6C high monocytes of GPSM1 f/f and GPSM1 f/f ; Lyz2-cre mice both under the NCD (n = 5 biologically independent mice per group) and HFD (n = 6 biologically independent mice per group) conditions. d to g Male GPSM1 f/f ; Lyz2-cre mice and age-matched GPSM1 f/f littermates were fed a HFD for 12 weeks. HFD feeding started at 7 weeks of age. d, Quantification of the proportion of crown-like structure (n = 5 biologically independent mice per group). e, Gating strategy for analysis of macrophages in eWAT and scWAT. f, The numbers of TIM4 + and TIM4macrophages of eWAT and scWAT (n = 3 biologically independent mice per group). g, Quantification of the proportion of Trichrome C + area (n = 5 biologically independent mice per group). h and i Male GPSM1 f/f ; Lyz2-cre mice and agematched GPSM1 f/f littermates were fed a HFD for 5 weeks. HFD feeding started at 7 weeks of age. h, GTT and ITT (n = 9 biologically independent mice for GPSM1 f/f and n = 10 biologically independent mice for GPSM1 f/f ; Lyz2-cre). i, Representative H&E and F4/80 + staining of eWAT sections and quantification (n = 4 biologically independent mice per group). Scale bars, 100 μm. All data are presented as means ± SEM. P values are determined by unpaired two-tailed Student's t-test (a to d, f, g, i) or two-way ANOVA with Sidak's multiple-comparisons test (h).

Supplementary Fig.6 GPSM1 depletion does not affect inflammatory properties of neutrophils and characterization of CSF1R-adminstered mice fed a HFD.
a and b Male GPSM1 f/f ; Lyz2-cre mice and age-matched GPSM1 f/f littermates were fed a HFD for 12 weeks. a, The myeloperoxidase (MPO) activity in eWAT (n = 4 biologically independent sample per group). b, RT-qPCR analysis indicating mRNA abundance of neutrophil inflammatory markers from sorted CD11b + Ly6G + neutrophils from the eWAT by flow cytometry (n = 4 biologically independent sample per group). c to f GPSM1 f/f and GPSM1 f/f ; Lyz2-cre mice, which had been already HFD-fed for 5 weeks, injected intraperitoneally CSF1R antibody or isotype IgG (10 mg/kg), twice a week, for 5 weeks. c, Flow cytometry quantification of total macrophages of eWAT (n = 3 biologically independent mice per group). d, Body weight curve (left) and the body weight at 10-week HFD (right). n = 6 biologically independent mice for GPSM1 f/f injected with IgG or CSF1R and GPSM1 f/f ; Lyz2-cre injected with IgG; n = 7 biologically independent mice for GPSM1 f/f ; Lyz2-cre injected with CSF1R. e, GTT and AOC (n = 5 biologically independent mice per group). f, ITT and AOC (n = 5 biologically independent mice for GPSM1 f/f injected with IgG or CSF1R and GPSM1 f/f ; Lyz2-cre injected with CSF1R; n = 6 biologically independent mice for GPSM1 f/f ; Lyz2-cre injected with IgG). All data are shown as means ± SEM. P values are determined by unpaired two-tailed Student's t-test (a to c), two-way ANOVA with Tukey's multiple-comparisons test (d to f) or one-way ANOVA with Tukey's multiple-comparisons test (d to f). Supplementary Fig.7 Metabolic cage studies of NCD-and HFD-fed mice.
a Food intake and Activity counts of NCD-fed mice (n = 6 biologically independent mice for GPSM1 f/f and n = 3 biologically independent mice for GPSM1 f/f ; Lyz2-cre) were monitored for a 24 h period. b Food intake and Activity counts of HFD-fed mice (n = 7 biologically independent mice for GPSM1 f/f and n = 5 biologically independent mice for GPSM1 f/f ; Lyz2cre) were monitored for a 24 h period. Throughout, data are presented as means ± SEM.  Data are presented as the mean ± SD or median (interquartile range) or n.
Comparisons are done using two-tailed Student's t-test.